1. Technical Field of the Invention
The present invention relates to an aqueous dispersion with excellent moisture resistance, insulation properties, antistatic properties, heat resistance, color fastness and the like, which contains polymer particles with suitable hardness and strength and which has a specific limited surfactant content. Another invention further relates to an aqueous dispersion composition for chemical mechanical polishing used for wafer polishing (hereunder referred to as xe2x80x9cdispersion compositionxe2x80x9d or xe2x80x9cCMP slurryxe2x80x9d) that contains specific polymer particles, or to a CMP slurry that has a specific limited surfactant content, to particularly a CMP slurry for chemical mechanical polishing used for wafer polishing.
Further, another invention relates to an aqueous dispersion containing polymer particles with a specified mean particle size. Further another invention relates to a CMP slurry with above-mentioned aqueous dispersion, to particularly a CMP slurry which is useful for chemical machine polishing of working films. Further another invention relates to a polishing process comprising a step of polishing a wafer working film with above-mentioned specific CMP slurry. And another invention relates to a process for manufacture of a semiconductor device using the CMP slurry.
2. Prior Art
Aqueous dispersions containing fine polymer particles are used, or are being studied for use, as electronic materials, polishing materials, coating materials, paints, optical materials, catalysts, photocatalysts, electronic material film lubricants, diagnostic agents, drugs, cosmetics, conductive materials, inks, CMP slurries and the like. However, conventional aqueous dispersions have presented the following problems when applied for these purposes.
(a) Because they contain impurities such as surfactants, they can result in quality reduction when applied for these purposes.
(b) Because the antistatic properties, heat resistance, color fastness, and the like of the polymer particles are not always adequate, their use is limited depending on the purpose.
(c) Their uses are also limited because the hardness of the polymer particles is low and their strength is insufficient.
While the use of aqueous dispersions containing inorganic particles has also been studied, inorganic particles present problems because their hardness is too hard and particles with uniform shapes are difficult to obtain.
The higher integration of LSIs in recent years has led to the development of a variety of different fine working techniques. For example, the minimum working dimensions for patterns are becoming smaller year by year, and at the current time they have already reached the submicron level. A variety of techniques such as chemical mechanical polishing (hereunder, xe2x80x9cCMPxe2x80x9d) have also been developed to meet the stringent demands of such fine working. CMP is an essential technique for planarizing of working film surfaces such as interlayer insulation films, formation of plugs, formation of molded-in metal wiring, separation of molded-in elements, and the like.
Aqueous dispersions containing abrasive particles made of metal oxides have conventionally been used as polishing materials in CMP. However, these abrasive particles have high hardness and have therefore presented the problem of creating scratches on polishing wafer surfaces. These scratches generated during the CMP process are not desirable because they lower the reliability of the LSI.
Improvements in wafer integration, increased multilayer wirings, and the like have led to the introduction of CMP techniques for polishing of working films and the like. As disclosed in Japanese Laid-Open Patent Publication Nos. shou-62-102543, shou-64-55845 and hei-5-275366, Japanese Patent Public Inspection No. hei-8-510437, Japanese Laid-Open Patent Publication Nos. hei-8-17831, hei-8-197414, and hei-10-44047 and elsewhere, there is known a type of process whereby a wiring material such as tungsten, aluminum, copper or the like is embedded in a hole or groove formed in an insulating film on a processing wafer and then polishing is performed to remove the excess wiring material to thereby form the wiring.
In this CMP process, aqueous dispersions containing metal oxide abrasive particles have traditionally been used as polishing materials. However, these abrasive particles have high hardness and have, therefore, presented the problem of creating nicks on polishing wafer surfaces. These nicks generated during the CMP process are not desirable because they lower the reliability of the LSI. In order to prevent such nicks, Japanese Laid-Open Patent Publication No. 9-285957 has proposed a polishing material having abrasive particles made of colloidal silica or the like, with the inclusion of scratch-preventing particles made of polyurethane resin or the like, having a larger size than the abrasive particles. However, when polishing materials containing such large-sized, low hardness scratch-preventing particles are used, this has presented the problem of a vastly reduced polishing rate compared to polishing materials containing abrasive particles made of metal oxides.
Japanese Laid-Open Patent Publication No. 7-86216 describes a polishing material (particularly CMP slurry) containing abrasive particles composed mainly of an organic polymer compound or the like instead of abrasive particles made of a metal oxide. It is explained that using the polishing material for polishing of wafer working films can prevent generation of nicks in the polishing wafer surface. However, abrasive particles made of this organic polymer compound have low hardness, and polishing materials composed mainly of these abrasive particles also give vastly lower polishing rates compared to polishing materials containing abrasive particles made of metal oxides.
Thus, the inventions described in these patent publications cannot achieve highly reliable high-speed polishing of working films for manufacture of semiconductor device (including various devices (wafers, device comprising wafer and the like)), nor do they allow efficient manufacture of wafers.
It is an object of the present invention to provide an aqueous dispersion and a CMP slurry with excellent moisture resistance, insulation properties, antistatic properties, heat resistance, color fastness and the like, which contains polymer particles with suitable hardness and strength, has few impurities such as surfactants, and is useful for such purposes as electronic materials, polishing materials, paints, drugs, inks and the like, as well as for polishing of magnetic disks, wafers and the like.
Further, it is another object of the present invention to provide a CMP slurry used for polishing of wafers, that can achieve polishing at an adequate rate without producing scratches in the polishing surfaces of wafer working films. It is yet another object of the present invention to provide a polishing process for wafer surfaces that comprises a step of polishing working films on wafers using the CMP slurry. Further, it is another object of the invention to provide a manufacturing process of a semiconductor device using the CMP slurry.
According to the present invention, the aforementioned objects of the invention are achieved by providing the following aqueous Dispersion, CMP slurry, a polishing Process for Wafer Surfaces, and a process for manufacture of a semiconductor device.
An aqueous dispersion characterized by containing polymer particles with a crosslinked structure and a mean particle size of 0.13-0.8 xcexcm.
An aqueous dispersion according to claim 1, wherein said polymer is produced by copolymerization of 5-80 wt % of a crosslinkable monomer and 20-95 wt % of another monomer.
An aqueous dispersion according to claim 2, wherein a surfactant is also contained , and said surfactant content is no greater than 0.15 wt % .
An aqueous, wherein said polymer particles have a hydrophilic group.
An aqueous dispersion, wherein said hydrophilic group is at least one from among hydroxyl, carboxyl groups and salts thereof, acid anhydride groups, sulfonic acid groups and salts thereof, phosphoric acid groups and salts thereof, and amino groups and salts thereof.
An aqueous dispersion, wherein further an oxidizing agent and/or a polyvalent metal ion is also included.
An aqueous dispersion, characterized by containing polymer particles and inorganic particles, wherein a mean particle size of said polymer particles is not more than a mean particle size of said inorganic particles.
An aqueous dispersion, wherein said mean particle size of said polymer particles is at least 0.1 xcexcm and less than 0.7 xcexcm, said mean particle size of said inorganic particles is greater than 0.1 xcexcm and no greater than 0.7 xcexcm, and a ratio of said mean particle size of said polymer particles and said mean particle size of said inorganic particles (Sp/Si ratio) is 0.05-0.85.
An aqueous dispersion, characterized by containing polymer particles and inorganic particles, wherein the mean particle size of said inorganic particles is 0.1-1.0 xcexcm, and is smaller than the mean particle size of said polymer particles.
An aqueous dispersion, wherein a ratio of said mean particle size of said polymer particles (Sp) and a mean particle size of said inorganic particles (Si) (Sp/Si ratio) is 1.1-20.
A CMP slurry, characterized by containing polymer particles with a crosslinked structure and a mean particle size of 0.13-0.8 xcexcm.
A CMP slurry, wherein said polymer is produced by copolymerization of 5-80 wt % of a crosslinkable monomer and 20-95 wt % of another monomer.
A CMP slurry, wherein a surfactant is further included, with the surfactant content being no greater than 0.15 wt %.
A CMP slurry, wherein said surfactant content is no greater than 0.05 wt %.
A CMP slurry, wherein said polymer particles have a hydrophilic group.
A CMP slurry, wherein said hydrophilic group is at least one from among hydroxyl, carboxyl groups and salts thereof, acid anhydride groups, sulfonic acid groups and salts thereof, phosphoric acid groups and salts thereof, and amino groups and salts thereof.
A CMP slurry, wherein an oxidizing agent and/or a polyvalent metal ion is also included.
A CMP slurry, wherein an organic acid is also included.
A CMP slurry, characterized by containing polymer particles and inorganic particles, wherein a mean particle size of said polymer particles is not more than a mean particle size of said inorganic particles.
A CMP slurry, wherein said mean particle size of said polymer particles is not less than 0.01 xcexcm and less than 5 xcexcm, and said mean particle size of said inorganic particles is greater than 0.01 xcexcm and not more than 5 xcexcm.
A CMP slurry, wherein said ratio of said mean particle size of said polymer particles (Sp) and said mean particle size of said inorganic particles (Si) (Sp/Si ratio) is 0.01-0.95.
A CMP slurry, wherein said mean particle size of said polymer particles is not less than 0.1 xcexcm and less than 0.7 xcexcm, said mean particle size of said inorganic particles is greater than 0.1 xcexcm and not more than 0.7 xcexcm, and said ratio of said mean particle size of said polymer particles and said mean particle size of said inorganic particles (Sp/Si ratio) is 0.05-0.85.
A CMP slurry, wherein further an oxidizing agent and/or a polyvalent metal ion are/is contained.
A CMP slurry, which further contains an organic acid.
A CMP slurry, characterized by containing polymer particles and inorganic particles, wherein said mean particle size of said inorganic particles is 0.1-1.0 xcexcm, and is smaller than said mean particle size of said polymer particles.
A CMP slurry, wherein said ratio of said mean particle size of said polymer particles (Sp) and said mean particle size of said inorganic particles (Si) (Sp/Si ratio) is 1.1-20.
A CMP slurry, wherein said mean particle size of said inorganic particles is 0.15-0.4 xcexcm, and said Sp/Si ratio is 1.1-5.
A CMP slurry, which further contains an oxidizing agent and/or a polyvalent metal ion.
A CMP slurry, which further contains an organic acid.
A polishing process for wafer surfaces characterized by using a CMP slurry that contains polymer particles with a crosslinked structure and a mean particle size of 0.13-0.8 xcexcm, for polishing of a working film formed on a wafer surface.
A polishing process for wafer surfaces, wherein said polymer is produced by copolymerization of 5-80 wt % of a crosslinkable monomer and 20-95 wt % of another monomer.
A polishing process for wafer surfaces, wherein said surfactant content is no greater than 0.05 wt %.
A polishing process for wafer surfaces, wherein said polymer particles have a hydrophilic group.
A polishing process for wafer surfaces, wherein said hydrophilic group is at least one from among hydroxyl, carboxyl groups and salts thereof, acid anhydride groups, sulfonic acid groups and salts thereof, phosphoric acid groups and salts thereof, and amino groups and salts thereof.
A polishing process for wafer surfaces, wherein said CMP slurry also contains an oxidizing agent and/or a polyvalent metal ion.
A polishing process for wafer surfaces, wherein said CMP slurry also contains an organic acid.
A polishing process for wafer surfaces, wherein said working film is a silicon oxide film, amorphous silicon film, polycrystalline silicon film, single-crystal silicon film, silicon nitride film, pure tungsten film, pure aluminum film, pure copper film, an alloy film of tungsten, aluminum or copper with another metal, or a tantalum or titanium oxide or nitride film, formed on a wafer.
A polishing process for wafer surfaces characterized by using a CMP slurry which contains polymer particles and inorganic particles, wherein a mean particle size of said polymer particles is not more than a mean particle size of said inorganic particles, for polishing of a working film formed on a wafer surface.
A polishing process for wafer surfaces, wherein said mean particle size of said polymer particles is not less than 0.01 xcexcm and less than 5 xcexcm, and said mean particle size of said inorganic particles is greater than 0.01 xcexcm and not more than 5 xcexcm.
A polishing process for wafer surfaces, wherein said working film is a silicon oxide film, amorphous silicon film, polycrystalline silicon film, single-crystal silicon film, silicon nitride film, pure tungsten film, pure aluminum film, pure copper film, an alloy film of tungsten, aluminum or copper with another metal, or a tantalum or titanium oxide or nitride film, formed on a wafer.
A polishing process for wafer surfaces, wherein said CMP slurry further contains an oxidizing agent and/or polyvalent metal ion.
A polishing process for wafer surfaces, wherein said CMP slurry further contains an organic acid.
A process for manufacture of a semiconductor device characterized by manufacturing a semiconductor device by using a CMP slurry which contains polymer particles with a crosslinked structure and a mean particle size of 0.13-0.8 xcexcm.
A process for manufacture of a semiconductor device polishing, wherein a surfactant is further included, with the surfactant content being no greater than 0.15 wt %.
A process for manufacture of a semiconductor device characterized by manufacturing a semiconductor device by using a CMP slurry which contains polymer particles and inorganic particles, wherein a mean particle size of said polymer particles is not more than a mean particle size of said inorganic particles.
A process for manufacture of a semiconductor device characterized by manufacturing a semiconductor device by using a CMP slurry which contains polymer particles and inorganic particles, wherein said mean particle size of said inorganic particles is 0.1-1.0 xcexcm, and is smaller than said mean particle size of said polymer particles.
According to the aqueous dispersion of the present invention, it is possible to obtain aqueous dispersions with excellent moisture resistance, insulation properties, antistatic properties, heat resistance and color fastness, which contain polymer particles with suitable hardness and strength and few impurities, and which are useful for electronic materials, polishing materials, coating materials, paints, optical materials, catalysts, photocatalysts, electronic material film lubricants, diagnostic agents, drugs, cosmetics, conductive materials, inks and the like.
Aqueous dispersions containing hydrophilic polymer particles according to another present invention are particularly useful for such purposes as electronic materials, polishing materials and the like.
Further, according to a aqueous dispersion of the present invention it is also possible to obtain various polishing materials (particularly CMP slurry) that provide sufficient polishing rates without creating scratches on polishing wafer surfaces. That is, the aqueous dispersion of the present invention is particularly suitable for use as a xe2x80x9cpolishing materialxe2x80x9d as mentioned above. The polishing material (particularly CMP slurry) has excellent heat resistance and employs polymer particles with suitable hardness and strength as the abrasive grits, thus allowing polishing of magnetic disk plates and the like at adequate rates without creating scratches on the polishing surfaces.
The polishing material (particularly CMP slurry) may be one that contains the aqueous dispersion as the main component. Here, xe2x80x9cmain componentxe2x80x9d means that the aqueous dispersion is present at 85 wt % or greater, and especially 90 wt % or greater, while the polishing material may also contain prescribed amounts of a polishing accelerator or the like.
The CMP slurry of the present invention may be used as polishing material for polishing of working films on wafers to provide a high polishing rate without creating nicks in the wafer polishing surfaces. According to the polishing process of the present invention it is possible to accomplish high quality polishing at a high polishing rate, and without creating nicks in wafer polishing surfaces. The polishing process, therefore, allows efficient manufacture of high-quality wafers.
The present invention also makes it possible to easily avoid dishing and erosion. Dishing is a term for polishing-created depressions from a given flat surface at the center section of wiring with a relatively large wiring width such as 100 microns which is embedded in an insulating material, where the wiring is formed by polishing a wafer by a metal wiring-attached damascene method, using an aqueous dispersion composition supplied during the polishing. Erosion refers to depressions from a given flat surface at a section of high wiring density, for example, a wiring section with a wiring width of 4.5 microns and an insulation width of 0.5 microns, having a 90% density at a 5 micron pitch. When dishing and erosion are extensive, burn-out occurs more readily and the device yield is impaired. Minimizing dishing and erosion is important in chemical machine polishing techniques for damascene.